The invention relates to a double differential device for a vehicle, having a longitudinal differential section, wherein the longitudinal differential section has a longitudinal differential input, a longitudinal differential output and an axle output, having a transverse differential section, wherein the transverse differential section has a transverse differential input and two driven outputs, wherein the longitudinal differential output is in operative connection with the transverse differential input, and wherein the longitudinal differential section and the transverse differential section are each designed as a planetary spur wheel gear and are arranged coaxially with a common main axis of rotation, wherein the longitudinal differential section has a longitudinal differential planet carrier, and the transverse differential section has a transverse differential planet carrier, and wherein the longitudinal differential planet carrier and the transverse differential planet carrier are arranged in such a way as to be rotatable relative to one another.
In the case of vehicles with all-wheel drive, a driving torque coming from an engine or from a transmission connected to the output of the engine is generally split several times. Thus, on the one hand, the driving torque is distributed between the two driven axles via an interaxle differential and, furthermore, is often distributed to the driven wheels on one axle via an axle differential. In this case, it is possible to design the interaxle differential and the two axle differentials as separate subassemblies.
Another approach is taken in publication WO 2010/003505 A2. In this publication, it is proposed to design both the interaxle differential and an axle differential as planetary spur wheel gears and to accommodate them as a coupled subassembly in a common housing. The drive assembly thereby formed for motor vehicles with all-wheel drive thus has one input and three outputs, wherein two outputs are assigned to the driven wheels on the front axle and the third output is assigned to the driven rear axle. The interaxle differential and the axle differential each have a planet carrier, these being coupled to one another for conjoint rotation.
Publication DE 103 15 181 A1, which probably forms the closest prior art, likewise describes a drive assembly for motor vehicles which is of functionally similar design to the abovementioned drive assembly. In contrast to the previous drive assembly, the spiders of the axle differential and of the interaxle differential in the embodiment in FIG. 2 of the present publication are designed to be rotatable relative to one another. To be more precise, an ring gear of the interaxle differential is connected for conjoint rotation to a spider of the axle differential, wherein the spider carries the planet wheels of the axle differential. The spider is surrounded on both sides by ring gears, wherein each of the ring gears meshes with one of the planet sets and is simultaneously connected for conjoint rotation to the driven shafts.